It is known to use lighting systems in large areas in which lighting is grouped together for operation. One such system is described in EP-A-1239704. In the system described in EP-A-1239704, a central control unit controls a plurality of localised areas either directly by connection with a load within each localised area or via a support control unit connected to a load in one or more localised areas. The load in this case corresponds to a circuit group providing the lighting. Management of the local circuit groups is achieved using radio frequency (RF) networks. However, the control unit and support control units are always operational for the whole time that the light system is on, that is, lighting at least one of the localised areas.